The Royal Society of Literature is Britain's oldest, and some might say stuffiest, literary society. Its fellowship has traditionally consisted of the most eminent playwrights, novelists and poets in the country. Tom Stoppard, Seamus Heaney, Harold Pinter and Doris Lessing are among the current fellows.

So it is truly a sign of the times that the front cover of the annual RSL magazine for 2006 will be devoted to two graphic novelists. Posy Simmonds and Raymond Briggs were both made fellows of the society this year, the first in their genre to receive the honour. They are designing a cover for the journal together, which will trumpet the arrival of graphic novels as a respected literary form.

For Briggs, it is not before time. 'On the Continent, graphic novels have been as accepted as films or books for many years, but England has had a snobby attitude towards them. They've always been seen as something just for children,' he said. 'When my Father Christmas was published in 1973, many people didn't consider a strip cartoon to be a real book at all.

'Cartoonists share some of the blame for the fact that their art has not been taken seriously. Too much of it has been superheroes socking people and semi-obscene stuff. But lately there has been much more work with a dignified, serious subject-matter. And as a genre it's increasingly commercially viable.'

Briggs and Simmonds are the godparents of graphic fiction in the UK. But there are signs that the coming year could see the genre, which is now hugely diverse, creeping further into the mainstream. The cult Japanese 'manga' comics have exploded in popularity over the last 18 months, with the Waterstone's chain deciding this autumn to stock up to 175 manga titles in all its branches. It reports that sales of manga and other graphic novels rose by 58 per cent last year.

Films such as American Splendour, based on the semi-autobiographical work of the cartoonist Harvey Pekar, and David Cronenberg's History of Violence, based on the book by John Wagner, have helped to raise the profile of sophisticated American comics. In the US, graphic novels are now the strongest sector of growth in publishing.

'There is lots of talk about the potential size of the UK market in graphic novels because in the States it is growing hugely,' says Emma Hopkin, the managing director of Macmillan, which is launching a new graphic imprint, First Second Books, in the spring. 'It just feels right to do it now.'

Other British publishers showing interest in the genre include Gollancz, which launched Gollancz Manga earlier this year, and HarperCollins, which is bringing out Osamu Tezuka's epic manga biography of Buddha next year. It is also publishing Dragonslippers, a 'graphic diary' of an abusive relationship, by Rosalind Penfold, in January.

Some of the best-known continental graphic artists are being brought to Britain by smaller publishers. The specialists Typocrat are publishing the cult French book Six Hundred and Seventy-Six Apparitions of Killoffer in English at the end of this month.

Paul Gravett, author of Graphic Novels: Stories to Change your Life, argues that the form has finally come of age. 'There was a false dawn for graphic novels in the late Eighties and Nineties, but now a new generation has grown up with an awareness of the form,' he said.

'It's the logical next step for our culture. With the internet and all the design-oriented newspapers and magazines, we're used to processing images and text together.'

Only Dan Franklin, at Jonathan Cape, sounds a note of caution. He has spearheaded the movement towards graphic novels in the UK, publishing Dan Clowes's Ghost World, which was made into a major film, the highly acclaimed Jimmy Corrigan by Chris Ware, and recently Black Hole by Charles Burns, which has been hailed as 'the Ulysses of graphic fiction'.

'There are a lot of pure geniuses working in the form,' he said.

'But I don't believe it's going to become a truly mass phenomenon. A lot of people who would buy literary fiction find them impossible to read. And it's still difficult to get these books into the bookshops - they're still full of superheroes.'

Three of the best

Buddha by Osamu Tezuka, out 2006

Tezuka, who died in 1989, is known as 'the God of Manga' and has a museum dedicated to him in Japan. He is credited with inventing the large-eyes characteristic of Japanese animation, which he based on American cartoons such as Betty Boop and Mickey Mouse. Buddha, a 3,000-page epic in eight parts, charts the life of Prince Siddartha as he seeks enlightenment.

Six Hundred and Seventy-Six Apparitions of Killoffer, by Patrice Killoffer, out end of this month

Killoffer, a key mover in France's booming comic scene, co-founded cult publishers L'Association in 1990. This, his first book for six years, is a striking black-and-white comic without strips, panels or speech bubbles. On a journey from Paris to Montreal, Killoffer is beseiged by 676 horrific and hilarious apparitions of himself.

Black Hole, by Charles Burns, out now

Black Hole, 10 years in the making, has been hailed as the 'Ulysses of graphic fiction.' Set in surburban Seattle in the mid-Seventies, a strange plague has descended on the area's teenagers, transmitted by sexual contact. Each develops a different, sinister symptom - one has a strange vaginal slit on his neck, another a tail.